Found this hole in my block - should I be worried??

So I'm cleaning up my 351C ready to send to the machine shop, when out of the corner of my eye I spot this hole in the block casting next to the distributor mounting hole, in the valley/lifter area. The pic shows the hole about an inch diameter. The engine ran OK before I pulled it out, a bit of a lifter tick tick tick but I'm wondering if this hole is going to be a problem? Any thought welcome. Thanks gurus.

https://plus.google.com/u/0/photos?pid=5998790802089011554&oid=104755388345436418907

I don't see a pic

All good, just pulled mine apart today and same hole.

Yeah thats a casting process thing. Every Cleveland has that.

Yup..First time i seen the valley on a cleveland i thought the same thing...It's fine.

Yeah thats a casting process thing. Every Cleveland has that.

Click to expand...

Thanks for that bit of info. Strange casting flaw, looks like some projectile has blasted though and left this jagged hole. Sorry my photo link didn't work. The tinypic plugin looks like the go, but my anti spam blocker has left a blank area right next to the feild where you load the filename. Ahhh, computers!